Rollup merge of #81501 - calebcartwright:update-rustfmt, r=sanxiyn

update rustfmt to v1.4.34

Short summary: Various formatting fixes (several const generic related) and introduction of `imports_granularity` config option

Long summary copied from changelog:

#### Changed
- `merge_imports` configuration has been deprecated in favor of the new `imports_granularity` option. Any existing usage of `merge_imports` will be automatically mapped to the corresponding value on `imports_granularity` with a warning message printed to encourage users to update their config files.

#### Added
- New `imports_granularity` option has been added which succeeds `merge_imports`. This new option supports several additional variants which allow users to merge imports at different levels (crate or module), and even flatten imports to have a single use statement per item. ([PR rust-lang/rustfmt#4634](https://github.com/rust-lang/rustfmt/pull/4634), [PR rust-lang/rustfmt#4639](https://github.com/rust-lang/rustfmt/pull/4639))

See the section on the configuration site for more information
https://rust-lang.github.io/rustfmt/?version=v1.4.33&search=#imports_granularity

#### Fixed
- Fix erroneous removal of `const` keyword on const trait impl ([rust-lang/rustfmt#4084](https://github.com/rust-lang/rustfmt/issues/4084))
- Fix incorrect span usage wit const generics in supertraits ([rust-lang/rustfmt#4204](https://github.com/rust-lang/rustfmt/issues/4204))
- Use correct span for const generic params ([rust-lang/rustfmt#4263](https://github.com/rust-lang/rustfmt/issues/4263))
- Correct span on const generics to include type bounds ([rust-lang/rustfmt#4310](https://github.com/rust-lang/rustfmt/issues/4310))
- Idempotence issue on blocks containing only empty statements ([rust-lang/rustfmt#4627](https://github.com/rust-lang/rustfmt/issues/4627) and [#3868](https://github.com/rust-lang/rustfmt/issues/3868))
- Fix issue with semicolon placement on required functions that have a trailing comment that ends in a line-style comment before the semicolon ([rust-lang/rustfmt#4646](https://github.com/rust-lang/rustfmt/issues/4646))
- Avoid shared interned cfg_if symbol since rustfmt can re-initialize the rustc_ast globals on multiple inputs ([rust-lang/rustfmt#4656](https://github.com/rust-lang/rustfmt/issues/4656))
- Don't insert trailing comma on (base-less) rest in struct literals within macros ([rust-lang/rustfmt#4675](https://github.com/rust-lang/rustfmt/issues/4675))

diff --cc Cargo.lock
Simple merge